Shock temperatures of soda-lime glass measured by an optical pyrometer

Shock temperatures of soda-lime glass in a pressure range 52-110 GPa have been determined by using a radiation pyrometer in conjunction with a two-stage light gas gun. This pyrometer consists of two parts, i.e., an OMA which provides a radiation spectrum over a visible range(similar to 450 nm window) and a 4-channel PMT system which provides a time-varying behavior of shock temperatures. Obtained spectra are well fit by the Planck function with moderate emissivities, indicating that relatively homogeneous thermal radiation is the main component of radiation. Obtained shock temperatures range from 2800 K to 5700 K and they seem to represent glass temperatures in the liquid state. The Hugoniot is well described by a linear shockvelocity-particle velocity relation, u(s) = 0.16 + 1.92 u(p) km/s The results suggest that radiations from shocked materials in the liquid state, in contrast to radiations from shocked solids are more thermal and fit the Planck function well, even at lower temperatures, because emission characteristics of compressed solids such as those due to heterogeneous deformation cannot be generated in shocked materials in the liquid state.